Advance Access: Convex-Rod Derotation Maneuver on Lenke Type I Adolescent Idiopathic Scoliosis

Since Harrington-rod instrumentation using the distraction technique was introduced in 1960, scoliosis surgery correction techniques have changed dramatically. A common corrective technique for adolescent idiopathic scoliosis (AIS) is concave-rod derotation according to the principles described by Cotrel et al.1 Combined with sublaminar wires or hooks, this technique can provide a good 3-D correction.27

Satisfactory correction outcomes were recently reported in a series of studies that employed segmental pedicle-screw fixation.813 However, using this technique for concave-side correction is associated with many potential drawbacks including a smaller concave pedicle width for screw insertion,1416unacceptable screw proximity to the spinal cord and thoracic aorta (right thoracic curve) on the concave side,17,18 and screws prone to spinal cord following the rod-derotation maneuver, all of which would theoretically increase the risk for neurovascular deficits.16,19,20

A previous report stated that larger pedicles, relative safety of screw placement, and screw orientation away from the spinal canal in derotation occur in the convexity.21 However, few studies have evaluated surgical outcomes for the convex-rod derotation maneuver in treating Lenke type I AIS. We performed a retrospective comparison study of 81 Lenke type I AIS patients treated with convex- or concave-rod derotation maneuvers in our scoliosis center between July 2008 and September 2012 (all patients consented to publication of their image in Figures 1 and 2).

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